What do F and D mean at the end of numeric literals?

Question

I\'ve seen some of this symbols, but I cannot find anything strange with it,

double d = 5D;
float f = 3.0F;

What does the D and F behind 5

Answer 1

D stands for double and F stands for float. You will occasionally need to add these modifiers, as 5 is considered an integer in this case, and 3.0 is a double.